The present invention relates to cross country floating vehicles and pneumatic tyres for such vehicles.
Wheel-mounted vehicles with pneumatic tyres are known, for which total displacement of wheels fitted with tyres allows them to cross water obstacles, not resting on bottom (RU No. 2042560, B 62D 61/00, 1995).
Such vehicles work on deformable grounds successfully also with a carrying capacity more than 0.05 MPa without destruction of a vegetal soil layer. However moving on the grounds with a carrying capacity less than 0.05 MPa such vehicles have problems of increase of their cross country ability, fuel economy, and also safety of a vegetal soil layer because of its considerable deformation.
Carrying capacity of a ground hereinafter is understood to be a contact pressure, at which there is spontaneous subsiding of a ground.
The wheel-mounted vehicles with pneumatic tyres are known also, for which total displacement of wheels fitted with tyres allows them to cross water obstacles, not resting on bottom, and the ratio of a mass of each tyre to its interior volume varies between 5.0-70.0 kg/m3 (RU No. 2084366, B 62D 57/00, B 62D 61/00, 1997).
Such vehicles can work on deformable grounds with a carrying capacity more than 0.03 MPa without destruction a vegetal soil layer.
However the problems of an increase of cross country ability and fuel economy, and also safety of a vegetal soil layer remain for these vehicles on grounds with a carrying capacity 0.03 MPa and less.
The pneumatic tyres containing side walls and ground engaging portion are known, for which the thicknesses of the side walls and of the ground engaging portion are identical and range between 0.01-0.015 of the section height (RU 2005083, B 60C 5/00, 1993).
Such tyres can work with interior pressure 0.01 MPa and do not ensure average pressure in a contact zone with a ground less than 0.02 MPa. If interior pressure in the tyre is less than 0.01 MPa cross folds appear on the thin ground engaging portion of the tyre, which create increased local pressures on the ground destroying a vegetal soil layer. Therefore vehicles with such tyres can work without destruction of a vegetal soil layer only on grounds with a carrying capacity more than 0.03MPa. Moving of the vehicles with such tyres without destruction of a vegetal soil layer is rather problematic on grounds with a carrying capacity 0.03 MPa and less.
Pneumatic tyres containing side walls, ground engaging tread portion and double-ply cord carcass are known also, with thickness of the carcass in a ground engaging tread portion and side walls equal 0.003-0.08 of section height of the tyre with interior pressure in it 0.01-0.03 MPa. (RU 2042530, B 60C 5100, 5/12, 1995).
If interior pressure is lower 0.01 MPa folds appear on the side walls of such tyres and it promotes an increase of rolling resistance and a deterioration of a controllability of the vehicles.
Therefore while moving with such tyres on grounds with a carrying capacity 0.03 MPa and less there are problems also of increase of cross country ability and safety of a vegetal soil layer, which have not been soluted in a known level of engineering.
Object of the invention is the creation of a cross country floating vehicle capable to work efficiently on deformable grounds with a carrying capacity 0.03 MPa and less without destruction of a vegetal soil layer, and of a pneumatic tyre for said vehicle working with interior pressure 0.005 MPa.
This problem is soluted by means of such design relations and parameters of a vehicle and a pneumatic tyre for said vehicle which provide engineering results in the form of increase of cross country ability and fuel economy of the vehicle on deformable grounds with a carrying capacity 0.03 MPa and less saving a vegetal soil layer, and also in the form of increase of the velocity of its moving on water and facilitation of its moving out of water on coast and ice.
For this purpose in the wheel-mounted vehicle containing the wheels fitted with pneumatic tyres, the total mass of the vehicle is connected with the tyre dimensions by the following relation:                     M                  D          ⁢                      xe2x80x83                    ⁢          B          ⁢                      xe2x80x83                    ⁢          n                    ⁢              10                  -          5                      =          0.001      -              0.006        ⁢                  xe2x80x83                ⁢        M        ⁢                  xe2x80x83                ⁢        Pa              ,
where:
Mxe2x80x94total mass of the vehicle, kg
Dxe2x80x94overall diameter of the tyre, m
Bxe2x80x94section width of the tyre, m
nxe2x80x94number of wheels of the vehicle, and the ratio of a mass of each tyre to its interior volume varies between 35-80 kg/m3.
The number n of wheels in the vehicle equals three or more.
The indicated relation connecting a total mass of the vehicle with the dimensions of the tyre, defines its conventional ground pressure. The real ground pressure depends on a total rigidity of the wheels fitted with pneumatic tyres characterized by the ratio of a mass of each tyre to its interior volume, and defines cross country ability, fuel economy and capacity of the vehicle to move on different grounds without destruction their vegetal soil layer.
Utiltzation of the claimed totality of the essential signs allows to receive for the vehicle the average ground pressure 0.008-0.009 MPa, that ensures an increase of its cross country ability and a decrease of fuel consumption on grounds with a carrying capacity 0.015-0.03 MPa saving their vegetal soil layer, and also an increase of the velocity of its moving on water and facilitation of its moving out of water on coast and ice.
For solution of the problem in the pneumatic tyre containing side walls and ground engaging tread portion, the ratio of a mass of the tyre to its interior volume varies between 35-80 kg/M3, and the percent radial deflection of the tyre with atmospheric interior pressure under the influence of its own mass and a mass of the wheel ranges between 15-45% of the tyre section height.
The working interior pressure in the tyre equals 0.005-0.05 MPa.
The tyre section width is more than the tyre section height.
The side walls thickness of the tyre ranges between 0.0025-0.0050 of its overall diameter, and the thickness of the ground engaging tread portion varies between 1.5-2.0 of said side wall thickness.
The pattern of the ground engaging tread portion has recesses and bosses and the latter are distributed on the surface of the ground engaging tread portion uniformly and their height does not exceed 0.015 of the overall diameter of the tyre, and the ratio of the boss surface area to the total surface area of the ground engaging porton ranges between 0.1-0.2.
The tyre is made of oligomer material.
The tyre contains the cord plies carcass, cords of which form an angle to a meridian of said tyre.
The tyre contains the inner tube.
The ratio of a mass of the tyre to its interior volume defines a total rigidity of the tyre with the wheel including own rigidity of the tyre and resiliency of air. The average ground pressure in a zone of contact of the tyre with a ground depends on this rigidity mainly when interior pressure in the tyre is above 0.01 MPa. If interior pressure in the tyre is 0.01 MPa and less its own rigidity is the key factor influencing on the average pressure in a zone of contact of the tyre with a ground. This rigidity is characterized by a relative radial deflection of the tyre with atmospheric interior pressure under the influence of its own mass and mass of the wheel.
Utiltzation of the claimed totality of the essential signs of the tyre by the way of limits of parameters describing a total rigidity of the tyre with the wheel and own rigidity of the tyre, ensures the average pressure in a zone of contact with a ground ranging between 0.008-0.009 MPa with interior pressure in the tyre 0.005 MPa.
It allows to increase cross country ability and fuel economy of the vehicle with these tyres moving on grounds with a carrying capacity 0.015-0.03 MPa and to save a vegetal soil layer.
If the side walls thickness of the tyre varies between 0.0025-0.0050 of its overall diameter, and the tyickness of the ground engaging tread portion ranges between 1.5-2.0 of said side wall thickness, it allows to distribute an own rigidity of the tyre along its profile in such a way, that with interior pressure in the tyre 0.005 MPa not only decreasing of ground pressure and its optimum distribution in a zone of contact are ensured, but also the stability of the tyre profile shape is maintained.
The side walls thickness of the tyre depends on its overall diameter because the latter has a decisive influence on the cross country ability of the vehicle.
The tread pattern consisting of recesses and bosses, distributed on a surface of the ground engaging tread portion of the tyre uniformly, with recesses height not exceeding 0.015 of the tyre overall diameter, and with the the ratio of the boss surface area to the total surface area of the ground engaging tread portion equaled 0.1-0.2, promotes uniform ground stabilization in a contact zone without its destruction and improvement of adhesion of tyres.
The application of an oligomer material allows to simplify manufacture of the tyres useing the process of die casting.